Re: silent hang - can anyone explain?

["Robert G. Jakabosky" <bobby@...>]

On Tuesday 16, David Collier wrote:
> I mistakenly wrote:
> 
>     for charIndex = startIndex, #payLoad
>     do
>         local char = payLoad:subs(charIndex, charIndex)
> 
> of course it should have been sub()
> 
> my program silently hung - is this an expected consequence of this
> sort of misspelling?

Lua might be doing a full GC before printing the error.  Run the 
program under a debugger and when it hangs pause it and check the 
stack trace.  The hang could be cause by some __gc function.

A user of my lua-zmq bindings ran into a similar hang [1].  The hang 
happened because two objects where not being closed in the correct 
order.  One object still had a live reference, but the other didn't.

An easy way to check is to wrap your main script inside a pcall()

print(pcall(function(...) -- first line

-- Lua code for your main script here.

end, ...)) -- last line


1. https://github.com/Neopallium/lua-zmq/issues/32

-- 
Robert G. Jakabosky